1. Field of the Invention
This invention is directed to a method for synthesizing aromatic dihydroxy diacid dihalides and to precipitates made from such method.
2. Description of Related Art
Conversion of aromatic dihydroxy diacids into isolatable aromatic dihydroxy diacid dihalides has required the use of a solvent in the prior art. Otherwise a hydroxyl group on an aromatic ring would allow the compound to self-polymerize.
U.S. Pat. No. 3,515,695 discloses use of an aliphatic ether as a reaction medium to prepare 2,5-dihydroxyterephthaloyl chloride from its dicarboxylic acid. Aromatic dihydroxy diacids, however, have limited solubility in aliphatic ethers and require extended periods of heating to achieve conversion to the dihydroxy diacid dihalide.
U.S. Pat. No. 3,515,695 discloses heating for 24 hours to achieve conversion of 2,5-dihydroxyterephthalic acid to 2,5-dihydroxyterephthaloyl chloride.
A need is present for a new method for synthesizing aromatic dihydroxy diacid halides and precipitates.